Coat inside of flan with raspberry jam and then add custard, spreading till even.
Arrange halves of strawberries, starting at the outside edge, on top of the custard, carefully to fill the entire flan.
Add blueberries to fill all remaining spaces (or more!)
Prepare glaze according to package instructions, or prepare jam glaze as directed above.
Allow to cool slightly before spooning over fruit.
Chill for 2-3 hours and dust with icing sugar before serving.
Fresh cream can be substituted for the custard, if desired